As for the AD issue, the "lost connection" doesn’t really mean lost connection with ADS, it just didn't get time from AD Server, however, we already change the wording from "The ADS server xxx.yyy.com connection was lost." to "Unable to get AD server response while request for time checking, will check again in 30 minutes period." What actual is it, no need to pay attention to the log at the moment. The point is, if the NAS is able to login by AD account at that time, that means the ADS Server connection does not lost, the notification mail can be ignore.